Quantitative distribution of major functional phytoplankton types (PFTs) of the world ocean improves the understanding of the role of marine phytoplankton in the global marine ecosystem and biogeochemical cycles. Because phytoplankton pigments absorb light for photosynthesis, satellite sensors detecting the ocean color can monitor phytoplankton on the global scale with reasonable spatial and temporal resolution. The analysis of hyper-spectral satellite data with PhytoDOAS, a method of Differential Optical Absorption Spectroscopy (DOAS) currently specialized for SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Cartography) on ENVISAT (details in Bracher et al. 2009,
Sadegi et al. 2011), enables to extract the optical signature of marker pigments specific for certain PFTs. With including the calculation of the light penetration depth derived from the retrieval of inelastic scattering, the biomass (chl-a) of the PFTs is calculated and data from
2002-2011 have been processed. The lecture will give insight on the retrieval method and show the global maps of PFT distribution of four different dominant PFTs (diatoms, cyanobacteria, coccolithophores, dinoflagellates). In addition, results of evaluating the PHYTODOAS PFT products with in-situ data obtained from collocated pigment water samples analyzed via HPLC, with other satellite and model PFT products will be shown. The use of these global PFT satellite data sets for studying PFT bloom dynamics in specific oceanic regions or for evaluating an ecosystem model will be presented.
References:
Bracher A., Vountas M., Dinter T., Burrows J.P., Rottgers R., Peeken I. (2009) Quantitative observation of cyanobacteria and diatoms from space using PhytoDOAS on SCIAMACHY data. Biogeosciences 6: 751-764
Sadeghi A., Dinter T., Vountas M., Taylor B., Peeken I., Bracher A. Improvements to PhytoDOAS method for identification of major phytoplankton groups using high spectrally resolved satellite data. Ocean Sciences (submitted)